Portable saw-engine.



N. B. MiTCHELL & J. W. TAGGART, SR.

PORTABLE SAW ENGINE. APPLICATION FILED APR. 18, 1913.

. 1 1 60,938, I Patented Nov. 16,1915.

4 SHEETSSHEET l.

VVJTNESSES:

I W 74 (Z. WM. ATTORNEY.

CGLUBISIA RLANOGRAPH CO.,WASHINOTDN. D- C.

N. B. MITCHELL & J. W. TAGGART, SR.

PORTABLE SAW ENGINE.

APPLICATION FILED APR. 18. 1913.

5 w A M Y m m mm N. M R .s E 0 l .w .H Mm m A a W 1 1M Mflfi in & E 0 m%i 1 1 Twrh l /fl lrd coLuMnm PLANOGRAPH co., WASHINGTON. D. c.

NIB. MITCHELL & 1. W. TAGGART, SR-

PORTABLE'SAW ENGINE.

APPLICATION FILED APR.18.|913.

' Patented. Nov. 16, 1915.,

4 SHEETSSHEET 3- KLCK WITNESSES.-

ATTORNEY.

COLUMBIA PLANOGMPH 60.,WASHINGTON, n. CI

N. B. MITCHELL & J. W. TAGGART, SR.

PORTABLE SAW ENGINE.

APPLICATION FILED APR.1B, 1913.

1,160,938, I Patented Nov. 16, 1915. v

4 SHEETS-SHEET 4.

.95 WITNESSES: Y LVVENTORS:

6. Z MW. I ATTORNEX COLUMBIA PLANOGRAPH $0.,WASII1NUTON. 0.1:.

erase r rance @FFIQE.

NELSON B. MITCHELL AND Jonnvv. TAGGART, ea, or Innrannroms, INDIANA, Iassrcrlvons or ONE-THIRD TO ULRICI-I- G. REDELIMANN, or INDIANAPOLISINDIANA.

1 PORTABLE saw-Enema.

Patented Nov. 16, 1915.

Application filed April 18, 1913; Serial No. 761,876.

To all whom it may concern.

Be it known that we, NELSON B. MITCH- ELL and JOHN W. TAGGART, Sn,citizens of the United States, residing at Indianapolis, in the countyof Marion and State of Indiana, have invented a new and useful PortableSaw-Engine, of which the following is a specification, reference beinghad to the accompanying drawings and to the letters and figures ofreference marked thereon.

This invention relates to fluid-pressure engines, particularly of theportable type adapted for use in connection with portable saws, theinvention having reference more particularly to the valves and valvegearing for controlling the passage of the fiuid to and from the enginecylinders.

An object of the invention is to provide an improved engine that shallbe so constructed as to be adapted to be mounted on the frame of a chainsaw for directly driving the saw. v

A further object of the invention is to provide an improved oscillatingengine that shall be simple and so constructed as to permit of reversingthe direction of motion of the engine and vary the speed thereof, andwhich may be operated by means of either compressed air or steam.

A still further object of the invention is to provide a relatively smallandpowerful fluid-pressure engine of suitable construction for use inthe forests, especially in the operations of felling timber, withoutrequiring the services of expert attendants, and which shall be durableand economical in use. I I With the above mentioned and other objects inview, the invention consists in an oscillating engine having novelcontrolling valves andreversing valve gearing, and in the novel partsand combinations and arrangements of parts as hereinafter particularlydescribed and claimed.

Referring to the drawings, Figure 1 is a 7 plan of the improved enginemounted on a portable saw frame and shown in the position in which itmay be used when felling a tree; Fig. 2 is a fragmentary plan of thereverse or normally under side of the engine; Fig. 3 is a fragmentarysection approximately on the line A A in Fig. 2; Fig. 1 is a fragmentarysectional elevation approximatelyon the line B B in Fig. 1; Fig. 5 is anelevation of one of the engine cylin.

ders; Fig. 6 is a plan of the engine frame and saw frame, the enginecylinders and valves being in central section; Fig. 7 is a transversesection approximately on the hne C C in Fig. 5; Fig. 8 is a fragmentarysection approximately on the line D D looking upward in Fig. 1; Fig. 9is a fragmentary section reproducing a portion of Fig. 6 but showing thecylinder and valve in different positions; Fig. 10 is a perspective viewof oneof the valve guides; Fig. 11' is a fragmentary section on the lineD D in Fig. 1 withthe cylinder omitted; Fig. 12 is a plan of the engineframe; Fig. 13 is a frage mentary section approximately on the line E Ein Fig. 6; Fig. 1 1- is a fragmentary section on the plane of the line FF in Fig. 13; Fig. 15 is a fragmentary section approximately on the lineG G in Fig. 12 showing parts of the gearing connected with the en g neframe; Fig. 16 is a erspective view of one of the reversing or s iftinglinks of the valve gearing; Fig. 17 is a plan of one of the main valves;Fig. 18 is a perspective view of one of the valve seats; Fig. l9 isaperspective view of the engine slightly modified as to the arrangementof the main valves and the several parts of the valve gearing which areslightly modified; Fig. 20

is a fragmentary end view of the engine and frames; Fig. 21 is anenlarged section approximately on the line H 'H in Fig. 19.; Fig. 22 isa sectional view showing portions of the preceding figure in' relativelydifi'erent nosition' F1 23 is a fra' 'mentar section approximately onthe line I I in Fig. 21; and Fig. 2a is a fragmentary'plan of theimproved valve gearing.

In the different figures of the drawings. similar reference charactersindicate like elements or features of construction herein referred toand described. I

The improved engine frame preferably comprises a fiat frame or bed platesuitably formed so as to be relatively light and 1;

strong and includesa main portion 1 and a portion 2 extending laterallyfrom the portion 1, and also two brace bars '3 and 4 extending from theportion 1 and the portion 2. The frame has an ear 5on one end there- Fof and also a removable side plate 6 having anear 7 arranged opposite tothe ear 5, the opposite end of the frame having a handle 8 thereon. Abacking blade 9 for-guiding a saw is secured at one end to the earstherefrom at an acute angle to the backing blade 9; a guide member 14extends from heads, the remaining 5 and 7. The engine frame performs thefunction of a. headstock for the saw. A. suitable tail stock isprovided. which has ears 11 secured to the opposite end oflthe blade 9and it has alsoa handle 12.- A guide member 13 is suitably secured tothe engine frame or head stock and extends laterally the member-13parallel with the backing blade, and aguide member 15 extends from themember 14 to the tail stock 10 and is connected therewith so that aframefor a relatively long chain saw is provided in which guide wheels16' and 16 are mounted,

J another guide wheel 17 being mounted in the tail stock. Theengine'frame or head stockhas a suitable aperture 18 therein in a whicha main shaft 19is' rotatably mounted.

A driving wheel 20 is secured to the shaft et ween the portion 1 and theside plate 6, suitable space being provided, and a suitable chain saw 21extends about the driving wheel and the said guide wheels so as to runin contact with the backing blade 9. The main shaft 1- 9 has a crankdisk 22 fixed thereon which is provided with a crank 7 my pin23. v V I 4In the present case two-cylinders 24 and 25' are employed and aresubstantially alike, the middle portion ofthe cylinders being providedrespectively with trunnions and 27 that are rotatively mounted insuitable bearings 28 and 29 respectively with which the engine frame isprovided equidistant from the main shaft 19. One cylinder has two heads30 and 31 thereon, the other cylinder having heads 30 and 31 thereon,the heads 31 and'81 beingprovided with packingboxes 32 and 32respectively. Pistons 33and 33" are fitted into the two cylindersrespectively and are provided respectively with piston rods 34 andu35that extend through the packing boxes and are connected tothe crank pin23 in such manner as to eliminate the dead-center in operation! The wallof one cylinder has two relativelylong port openings 36 and 37 near thecylinder cylinder having similar openings 36 and 37. One cylinder ispreferably provided with two valve seats Y38 and 39-formed separatelyand suitably se- 1 cured to the exterior of the cylinder, the remainingcylinder being provided with similar valve seats 38" and 39. The valveseats 38 and '39 have ports 40 and 41 therein respectively that aresomewhat shorter longitudinally of the cylinder than the openings 36 and37 respectively,'and are'spaced so astoadmit fiuidto the opening at" theend thereof farthest from the cylinder head. the fluidpassing along thepiston in the port opening to the opposite end'of the opening whenthepiston is about to move awayfrom the cylinder head. The remaining twovalve arranged in a and 43-,"and 42 and 43 respectively,

' tending from the chamber 48 controlling the passage ofthe'fluid tively'with. nipples 55 and seats have similar ports 40 and 41 therein similarmannerrelative to the port openings 36 and 37. The several valve seatsare providedwithsuitable guides 42- for guiding two main valves 44 and45 of similar. construction for the respective cylinders, one valvehaving two slide members 46 and 47 arranged on the valve seats 88 and 39respectively, the remaining valve;hav-

' .ing two slide members 46 and-47 arranged on the seats. 38"and. 39"respectively. The valves have longitudinal chambers 48 and 48 thereinrespectively, two ports 49 and 50 extending from the chamber 48 throughthe face of the slide members 46 and 47 re spectively, tw'ojsimilarports 49 and 50 ex- I through the face of the slide members 46 and 47,for through the ports that are in the valve seats. The valves aresuitably maintained by their guides in close arrangement with the valveseats and are provided with valve stems 51 and 52- respectively, theends of the stems having lateral wrist-pins 53 and 54 respectively foroperating and controlling the valves. The relative proportion of thevalves and the valve seats permits the slide members "of he valves tomove across the valve seats to such extent as to prevent the formationof shoulders or transverse ribs on either the valves or the seats, sothat the natural wear does not necessitate frequent refacing. The valvesare provided respec- Y 1 '56 for conducting the fluid into the chambersof the valves. Preferably the bar has a. longitudinal chamber 57 formedin its middle portion with which is connected two nipples 5'8 and 59,and to the latter two rubber tubes 60 and 61 are: connected which areconnected also to the nipples'55 and'56 respectively for conducting thefluidhto the moving valves. The bar 3 is provided also with a nipple towhich is connected a rubber supply pipe or hose 63through whichcompressed air'or steam may be conducted and distributed to the enginecylinders.

In order to advantageously support the valve gearing the engine frame isprovided with two suitable apertures 64 and 65 which preferably arein'the brace bar 3adjacent to the portions 1 and 2 respectively of theengine frame. Two curved links 66 and 67 which are alike in form areprovided forre versing the motion of the engine and to cause the mainvalves thereofto control the admission of the actuating fluid, such ascompressed air, to the cylinders, the links being so constructed as to"permit'movable connection therewith of suitable devices connected withthe valves. Thelinks prefer ably arev curved and the 'middle' portionsthereof provided with backs 68 and 69 re- 1 the movement as betweenspectively on which are'trunnions and 71 that are rotative ly mounted.in the bearings 61 and 65 respectively. The links preferably havelongitudinal slots 72 and 73 therein respectively in which thewrist-pins 53 and 5% are respectively guided to cause relathe valves andthe cylinders when the latter oscillate. The slots in the linkspreferably are curved concentrically to the axes of rotation of thetrunnions of the cylinders. The links are provided with controlling arms'71 and 75 respectively for adjusting the links and holding them infixed position when adjusted, the arms preferably being secured to thetrunnions of the links. The engine frame is provided with a pivot 76 andalso a notched quadrant 77, a reverse lever 78 being connected to thepivot and provided with a latch 79 adapted for engagement with thequadrant. A red 80 is connected to the reverse lever and also to the arm7 4, a similar rod 81 being connected also to the reverse lever andtopthe arm 75, so that when the engine is at rest the links may beshifted or adjusted on operation of the reverse lever for moving thevalves and cause the engine to move either forward or backward as may bedesired.

hen the engine is constructed as above described, the main valves are onthe adjacent side portions of the cylinders, so that both valves operatebetween the two cylinders, and the engine is best driven by means ofco-i'npressed air which is exhausted from the cylinders through theports of the valve seats into the atmosphere when the valves uncover theports, as shown in Fig. 9 where the port 41 is uncovered.

In order to-adapt the engine for the use of steam and control theexhaust so asrto carry it away from the sawing machine and theattendants, the valve gearing is slightly modified as illustrated inFigs. 19 to 24 inclusive, in which are illustrated two cylin- I ders 82and 83 provided each with a trunnion 84 connecting the cylinders withthe engine frame so as to oscillate, one cylinder having heads 85 and86, the other having heads 85 and 86, each cylinder having a piston 87therein connected respectively to the pistonrods 34 and 35. Eachcylinder has a valve seat 88 thereon from which ports 89 and 90 extendto opposite end portions of the cylinder and from which an exhaust port91 also extends. The valve seats of the two cylinders are covered bysteam chests 92 and 92 respectively in each of which suitable valveoperates and preferably is of the common D-valve type 93, the valvesbeing provided respectively with valve stems 94 and 94. Two slottedreversing links 95 and 96, similar to those above described, areprovided each with a trunnion 97 rotatively mounted in the engine framein proximity to the outer end of the cylinders. Each link has a socketedslide block 98 that is movable longitudinally in the slot of the linkand guided therein. The links are provided respectively with controllingarms 99 and 99/1 The heads 85 and 85 of the cylinders have arms 100 and100 thereon respectively which support pivots 101, 101 respectively onwhich levers 102 and 102 are mounted between their ends, one end of thelevers being pivotally connected to the valve stems 94 and 94.respectively and practically forming continuations thereof. Each leverhas a ball 103 thereon that is inserted in the socket of the link block,and. the lever is guided and prevented from wabbling on its supportingpivot by a guide 10% with which the adjacent cylinder head 85 or 85 ispro vided. A reverse lever 105 is connected to the frame substantiallyas herein-before described and has a latch 106 to cooperate with thequadrant 77 for holding the lever. A rod 107 is connected. to the arm 99and a similar rod 108 is connected to the arm 99, both rods beingconnected to the reverse lever.

In order to supply the valve chests 92 and 9'2 with steam, a pipe 109 issuitably swiveled at its ends to the tops of the two steam chests and ithas a steam supply pipe 110 connected thereto, the arrangement beingsuch that the pipe 109 is stationary when the cylinders oscillate. Tworubber tubes 111 and 111 are suitably connected with the exhaust portsofthe two cylinders and are.

connected also to a metallic pipe 112 to which a rubber tube or hose 113is connected for conducting away the exhaust steam.

In practical use the reversing links are held stationarily so as to beeccentric to the axes of oscillation of the cylinders, being so adjustedand held by means of the reverse lever and when the cylinders oscillateand therefore move the controlling devices of the main valves laterally,the devices travel longitudinally of the links in guiding connectiontherewith and cause the valves to move longitudinally on their seats soas to open or close. the ports in the seats at the proper periods. InFig. 6 it will be seen that the reverse lever is in mid position and thevalves close allthe ports. It will be evidentthat if the reverse leverbe moved in one direction the valves will be shifted so that the enginewill start in one direction, and if the lever be mm'ed in the oppositedirection the valves will be shifted so that the engine will start andmove in the opposite direction. Normally the engine runs in thedirection indicated by arrows on Figs. 1, 6 and 19, but in case itbecomes necessary to back the saw the engine may be reversed so as torun in the opposite direction as indicated in Fig. 9. Other results ofthe operation of the'engine will be readily understood & 1,160.938

w from the foregoing description of the construction and arrangement ofthe various parts thereof. 7

Having thus described the invention, what is claimed as new is-- 1. In aportable saw engine, the combination of a frame, two cylinders spacedapart and mounted to oscillate on theframe, a crank shaft rotatablymounted in the frame, two pistons in the cylinders respectively andoperatively connected with the crank shaft, two" guide links supportedon the frame in proximity to the ends of the cylinders that are thefarther from the crank shaft, two valves movable on the cylindersrespectively for admitting fluid to the cylinders, and two controllingdevicesconnected to. the valves respectively and having sliding contactwith i the links respectively.

In a portable saw engine, the combination with a frame, of a cylindermounted to oscillate on oneportion ofthe frame, a second cylindermountedto oscillate on another portion of the frame, twolinks mount- 7ed adjustably on the frame, a lever pivotally connected to the frame,two rods connected with the two links respectively and also with thelever, and two movable valves for controlling admission of fluid to thetwo cylinders respectively and operatively connected with the two linksrespectively.

3. In a portable saw engine, the combinaticn of a frame having afluid-retaining chamber therein, two cyllnders mounted to oscillateon'the frame, two links mounted adjustably on the portion of the framethat has the chamber therein, a lever pivoted to the frame, two rodsconnected to the two links respectively andalso to the lever, twomovable valves for controlling admission of fluid to the two cylindersrespectively and operatively connected with the two. links respectively,each valve being guided on its cylinder and having a fluid-retainingchamber therein, and two laterally flexible pipes connected to the twovalvesrespectively and also with the chamber of said frame.

4. In a portable saw engine, the combination of a frame, twocylindersinounted to oscillate on the frame, each cylinder having arm ofthe remaining one of said links.

two ports, two valves movable on the cylinders respectively for openingor closing the ports thereof, two links mounted adjustably on saidframe, each link having a controlling arm, two operating connectionsconnected respectively with the two valves and movably with the twolinks, a lever pivotally connected with the said frame, a notchedquadrant fixedly supported by said frame adjacent to said lever, a latchmounted on said lever for engaging said quadrant, a

rod connected to the lever andalso to the controlling armof one of saidlinks, and a rod connected also to said lever and to the In a portablesaw engine, the combination of a frame,; a crank shaft rotatably mountedin the frame, acylinder having a trunnion rotatably mounted in saidframe, a piston movable in-said cylinder, a pitman connected to thepistonand the crank shaft, a valve movable on the cylinder forcontrolling admission of fluid to the cylinder, a guide link having atrunnion that is rotatably adjustable in the said frame, an arm fixed onthe trunnion ofsaid link, a controlling rod pivotally connected to saidarm,

and an operating connection for said valve connected with the valve andalso movably connected with said link. 7

(3. In a portable saw engine, the combina tion of a frame, a powercylinder mounted to oscillate on'the frame, a valve movable on thecylinder, a stem connected to the valve, a

guide linkmounted on the frame, an arm:

and a guide fixedly connected to the cylin- .der, the guide beingadjacent to the link, and

a lever pivoted between its ends to the arm and connected at one end tosaid stem, the opposite end portion of the lever being in movablecontact with said guide and also with said link.

In testimony whereof, we affix our. signatures 111 presence of twowitnesses.

Nansen-'13; MrrcnnLL." JOHN w. TAGGART, s11.

lVitnesses:

E. T. SILVIUS, lvLLL. WVILr-IELM.

Copies of this patent may be obtained for five cents each,by addressingthe Commissioner of Patents.

Washington, D. 0;

